Category Archives: Imperial Army Air Force

Japan

Kayaba Ka-1 (Frank-Airmodel, Resin)

TYPE: Autogyro, reconnaissance, observation

ACCOMMODATION: Crew of two

POWER PLANT: One Argus As 10c air-cooled engine (Ka-1) or Jacobs L-4MA-7 air-cooled radial engine (Ka-2), both rated at 240 hp

PERFORMANCE: 103 mph

COMMENT: By order of the Imperial Japanese Army (IJA) the Kayaba Industry developed an autogyro designated Kayaba Ka-1 for reconnaissance, artillery-spotting, and anti-submarine uses. The design based on an American Kellet KD-1A, which had been imported to Japan in 1939, but which was damaged beyond repair shortly after arrival. Kayaba Industry was tasked by the IJA to develop a similar machine, essentially a repaired Kellet KD-1A but powered by a German Argus As 10c engine and shared similar aspects to the German Focke-Wulf Fw 61, which was first flown in 1936, but only about 20 were produced.
The first Kayaba Ka-1 took off from Tamagawa Airfield in May 26, 1941. In the following Army trials, performance was deemed excellent. Originally, it was planned to send the Ka-1 to spot for the artillery units based in mainland China, but the change of the course of war in that theater rendered those plans meaningless. Instead, a few Ka-1 were sent to the Philippines to perform the duties of liaison aircraft as replacements for the Kokusai Ki-76. Soon, an improved version with a Jacobs L-4MA-7 radial engine was on the production line as Kayaba Ka-2. After some time the IJA finally decided on the best use of these unique aircraft, and the majority of Ka-1 and Ka-2 were pressed into service as anti-submarine patrol aircraft. Pilot training for this duty started in July 1943 with the first batch of 10 pilots graduating in February 1944; followed by another batch of 40 pilots in September 1944.
Originally, the plan was to deploy the Ka-1/Ka-2 from 2D-class cargo ships to spot enemy submarines, but these ships turned out to be too cramped for operations; therefore the Ka-1/Ka-2 unit was assigned to the Army-operated escort carrier Akitsu Maru from August 1944 until her sinking in November 1944. From 17 January 1945 ASW patrols were resumed from an airstrip on Iki Isaland with a maintenance base located at Gannosu Airfield in Fukuoka prefecture. ASW patrols also started from May 1945 from Izuhara airfield on Tsushima Island. These missions helped to protect one of the last operational Japanese sea lanes between the ports of Fukuoka and Pusan. Eventually US carrier-based aircraft began to appear even in the Tsushima Strait, so in June 1945 the Ka-1/Ka-2 units were relocated to Nanao base on the Noto Peninsula, in the Sea of Japan, operating from there until the end of the war. The Ka-1/Ka-2 did not directly sink any submarines during the war however, they were well regarded for issuing submarine warnings
A total of 98 Ka-1 and Ka-2 airframes were produced by the end of war, of them 12 were destroyed before being delivered to the IJA and about 30 never had an engine installed, about 50 were delivered to the IJA, but only 30 were actually deployed. Some sources have stated that 240 were built, but this cannot be verified (Ref.: 24).

Tachikawa Ki-54c (Army Type 1 Transport Model C), (“Hickory”), (A+V Models, Resin)

TYPE: Trainer and light transport aircraft

ACCOMMODATION: Crew of two plus eight passengers or equivalent cargo

POWER PLANT: Two Hitachi Ha-13a radial engines, rated at 510 hp each

PERFORMANCE: 233 mph

COMMENT: The Tachikawa Ki-54 was a Japanese twin-engine advanced trainer and light  transport aircraft used during WW II. The aircraft was developed in response to an Imperial Japanese Army Air Force requirement for a twin-engine multi-purpose trainer, principally for crew training. The prototype first flew in summer 1940 and, on completing trials, entered production in 1941 as “Army Type 1 Advanced Trainer Model A” (Tachikawa Ki-54a). The Ki-54a was soon followed by the Tachikawa Ki-54b as “Army Type 1 Operations Trainer Model B” and Tachikawa Ki-54c as “Army Type 1 Transport Model C”.
The Tachikawa Ki-54c was a light transport and communication version characterized by its smooth upper fuselage line and was fitted with eight seats. A similar version was built in small numbers as Tachikawa Y-59 for civil operators. Late in the war an all-wood version of the Ki-54c, the Tachikawa Ki-110 was built, but the aircraft was destroyed during an American air raid.
As a crew trainer and light transport, the Tachikawa Ki-54 was one of the most successful Japanese aircraft of the war and was well known to the Allies which named it “Hickory” regardless of the version. The code name “Joyce” was erroneously assigned to a non-existent light bomber version.
A total of 1,368 Ki-54 were built by Tachikawa Hikoki K.K. during the war. A few captured aircraft were flown after the war by various users (Ref.: 1, 24).

Mitsubishi Ki-46-II “Dinah”, 74th Dokuritsu Dai Shijugo Chutai (Matchbox Models, Parts Scratch-built)

TYPE: Reconnaissance aircraft

ACCOMMODATION: Crew of two

POWER PLANT: Two Mitsubishi Ha-112 radial engines, rated at 1,080 hp each

PERFORMANCE: 375 mph at 19,000 ft

COMMENT: To the Allied aircrews ”Dinah” was known as the aircraft with the nice “linah”. Indeed, the Mitsubishi Ki-46 had probably the most graceful lines of any fighting aircraft of WW II. Cleanly designed, reliable and fast, this airplane performed its unspectacular tasks of high-altitude reconnaissance with considerable success from the first unauthorized overflight of Malaya before the Japanese invasion of that country to the surveillance flights over the US 20th Air Force’s bases in the Marianas during the closing stage of the war. Respected by its foes and trusted by its crews, the Ki-46 also captured the attention of the German Luftwaffe with fruitlessly negotiated the acquisition of a manufacturing license under the Japanese-German Technical Exchange Programme.
Because of the geographical location of Japan and the vastness of the area in which a potential conflict requiring their participation would be fought, the Imperial Japanese Army had a constant requirement for reconnaissance aircraft combining high speed with substantial range performance.
On 12 December 1937, the Imperial Japanese Army Air Force issued a specification to Mitsubishi for a long-range strategic reconnaissance aircraft to replace the Mitsubishi Ki-15. The specification demanded an endurance of six hours and sufficient speed to evade interception by any fighter in existence or development. The resulting design was a twin-engined, low-winged monoplane with a retractable tailwheel undercarriage. It had a small diameter oval fuselage which accommodated a crew of two, with the pilot and observer situated in individual cockpits separated by a large fuel tank. Further fuel tanks were situated in the thin wings both inboard and outboard of the engines. The engines, two Mitsubishi Ha-26s, were housed in close fitting cowlings developed by the Aeronautical Research Institute of the Tokyo Imperial University to reduce drag and improve pilot view.
The first prototype aircraft, with the designation Ki-46, flew in November 1939 from the Mitsubishi factory at Kakamigahara, Gifu. Tests showed that the Ki-46 was underpowered, and slower than required, only reaching 336 mph rather than the specified 373 mph. Otherwise, the aircraft tests were successful. As the type was still faster than the Army’s latest fighter, the Nakajima Ki-43 “Hayabusa” (“Peregrine falcon”, Allied code “Oscar”), as well as the Navy’s new Mitsubishi A6M2 “Zero”, an initial production batch was ordered as the Army Type 100 Command Reconnaissance Plane Model 1 (Ki-41-I).
While testing of the Ki-46-I was going on, the engine plant of Mitsubishi had under development an advanced version of the Ha-26-I engine, the Ha-102, with two-speed supercharger which was expected to boost take-off rating to1,080 hp. With this powerplant it was anticipated that the Ki-46 could easily meet its speed requirement and consequently Mitsubishi were instructed to proceed with the design of the Ki-46-II to be powered by a pair of Ha-102s. The first Ki-46-II was completed in March 1941 and the test progressed satisfying so the production started.
The new aircraft was first used by the Japanese Army in Manchukuo and China, where seven units were equipped with it, and also at times by the Imperial Japanese Navy in certain reconnaissance missions over the northern coasts of Australia and New Guinea. The Imperial Japanese Army Air Force used this aircraft for the same type of missions over present-day Malaysia during the months before the Pacific War. Later, it was used for high altitude reconnaissance over Burma, Indochina, Thailand, and the Indian Ocean.  The Mitsubishi Ki-46 was regarded by the Allied as a difficult aircraft to counter, only occasionally intercepting them successfully.
During WW II Mitsubishi factories produced 34 units Mitsubishi Ki-46-I, and 1093 units Mitsubishi Ki-46-II (Ref.: 1, 24).

Kogiken Plan VIII High-Speed Reconnaissance Aircraft, (Unicraft Models, Resin)

TYPE: Fast reconnaissance aircraft, light bomber. Project

 

ACCOMMODATION: Crew of three

POWER PLANT: Four Mitsubishi Ha-211-II “Kinsai” (“Venus”) radial engines, rated at 1,075 hp each

PERFORMANCE: 481 mph (estimated)

COMMENT: In early 1941, Rikugun Kokugijutsu Kenkyujo (Japanese Army Aerotechnical Research Institute)  abbreviated “Kogiken”, formed a design group in order to study Japanese aviation technology in terms of what was possible at present and in the near future.
Of several high-speed reconnaissance aircraft concepts one of the designs was the Kogiken Plan VIII High Speed Reconnaissance aircraft. Including many concepts from Kogiken’s bomber design division, the Plan VIII aircraft was distinguished by its highly aerodynamic design. The cockpit for a crew of three was located at the tip of the fuselage, giving excellent view, and the glazing was flush with the rest of the airframe. Four Mitsubishi Ha-211-II radial engines were to be housed front-to-back in two stream-lined underwing engine nacelles, driving three-bladed tractor- and pusher propellers. Alternatively the Nakajima Ha-45 “Sakae” (“Prosperity”) radial engine, rated at 1,115 hp each could be installed. A tricycle landing gear was provided. The plane had a projected top speed of 481 mph and a maximum range of 1,864 miles. Due to its high speed no armament was provided. The design drawings were completed but although the calculated performance was promising the project was not realized (Ref: 24),

Mitsubishi Ki-202 “Shūsui-Kai” (“Sharp Sword”) (A + V Models, Resin)

TYPE: Interceptor aircraft. Project

ACCOMMODATION: Pilot only

POWER PLANT: One Mitsubishi Toku Ro.3 (KR20) liquid fuel rocket engine, rated at 2,000 kp thrust plus one additional rocket, rated at 750 kp thrust

PERFORMANCE: 559 mph at 32,808 ft

COMMENT: The Mitsubishi Ki-202 “Shūsui-Kai” (translated as “Sharp Sword, improved”) was a direct development of the Mitsubishi Ki-200 “Shusui” rocket-powered interceptor aircraft. None were produced before Japan’s surrender that ended WW II.
In a split from the development of the IJ Navy Mitsubishi J8M “Shusui” and Army’s Mitsubishi Ki-200 “Shusui”, the IJ Army instructed Rikugun Kokugijitsu Kenkyujo (Army Aerotechnical Research Institute) to develop a new design originally based  on the German Messerschmitt Me 163 “Komet” (“Comet”), built in Japan as a joint Navy-Army venture.
A fundamental shortcoming of the Messerschmitt Me 163, and all other aircraft based on it, was extremely limited endurance, typically only a few minutes. The Imperial Japanese Navy proposed to improve the endurance of the J8M1 by producing a version with only one cannon, thereby saving weight and space for more fuel, designated J8M2. The Imperial Japanese Army, on the other hand, opted to keep both cannon, but enlarge the airframe to accommodate larger tanks, resulting in the Mitsubishi Ki-202 “Shusui-Kai”, which was to have been the definitive Army version of the fighter. Power was to be supplied by a 2,000 kg thrust delivering Mitsubishi Toku Ro.3 (KR20) rocket motor. An additional rocket engine with reduced thrust was used for cruising speed. Undercarriage was to have been a sprung skid and tail-wheel.
Similar development was done in Germany. The Messerschmitt Me 163 variant Messerschmitt Me 163C had a lengthened fuselage to accommodate larger fuel tanks while the Messerschmitt Me 263 was a complete new design with increased flight endurance (Ref.: 24).

Kawasaki Ki-100-I Otsu, 5th Sentai (Hasegawa)

TYPE: Fighter

ACCOMMODATION: Pilot only

POWER PLANT: One Mitsubishi Ha 112-II radial engine, rated at 1,500 hp

PERFORMANCE: 360 mph at 19,700 ft

COMMENT: In mid-1944, the Kawasaki Ki-61”Hien” (Allied code “Toni”) was one of the best fighters of the Imperial Japanese Army Air Service. It was the only production Japanese fighter to have an in-line Kawasaki Ha-40 power plant, a Japanese adaptation of the German Daimler-Benz DB 601 engine, as well as the first one with factory-installed armor and self-sealing fuel tanks. It also had respectable performance, more in line with contemporary American and European designs of the time, with speed and rate of climb emphasized instead of maneuverability and range. It was an effective design, but suffered from engine shortages and reliability problems.
These problems as well as the performance advantage of enemy fighters, especially the Grumman F6F “Hellcat”, led to the development of an improved model, the Ki-61-II (later Ki-61-II-KAI), powered by the new 1,500 hp Kawasaki Ha 140 engine, which was unfortunately heavier than the Ki-61-I-KAIc it replaced. Maximum speed increased from 370 to 380 mph as well as general performance. However, it was never able to perform as planned due to the continued degradation of quality of the engine’s assembly line, with far fewer engines produced than were required, while many of the engines that were built were rejected due to poor build quality. At this point of the war, the IJAAF was in desperate need of effective interceptors to stop the enemy bomber raids over the Japanese mainland, so in October 1944 it was ordered that a 1,500 hp Mitsubishi Ha 112-II “Kinsei” (“Venus”), a 14-cylinder, two-row radial engine should be installed in those airframes. The need for the re-engined fighter was made yet more urgent on January 1945, when a Boeing B-29 “Superfortress” raid destroyed the engine’s production plant, leaving 275 finished Ki-61s without a power plant.
The Mitsubishi Ha-112-II was some lighter than the Ha-140 and produced the same power more reliably. After the study of an imported German Focke-Wulf Fw 190, an example of an aircraft in which a wide radial engine had been successfully installed in a narrow airframe, three Kawasaki Ki-61-II-KAI airframes were modified to carry this engine and to serve as prototypes.  As a result, on February 1945, the new model, Kawasaki Ki-100, was flown for the first time. Without the need for the heavy coolant radiator and other fittings required for a liquid-cooled engine, the Ki-100 was lighter than the Ki-61-II, resulting in a reduction of wing loading. This had an immediate positive effect on the flight characteristics, enhancing landing and takeoff qualities as well as imparting increased maneuverability, including a tighter turning circle.
The army general staff was amazed by the flight characteristics of the plane, which surpassed the Ki-61 in all but maximum speed (degraded by a maximum of 18 mph]by the larger area of the radial engine’s front cowling, and the model was ordered to be put in production. The company’s name was Ki-100-1-Ko. All of the airframes were remanufactured from Ki-61-II Kai and Ki-61-III airframes; the integral engine mount/cowling side panel was cut off the fuselage and a tubular steel engine mount was bolted to the firewall/bulkhead. Many of the redundant fittings from the liquid-cooled engine, such as the ventral radiator shutter actuator, were still kept. The first 271 aircraft, or Kawasaki Ki-100-1-Ko, with the raised “razorback” rear fuselage were rolled out of the factory between March and June 1945. A further 118 Ki-100 I-Otsu are built with a cut-down rear fuselage and new rear-view canopy from May through to the end of July 1945. This version also featured a modified oil cooler under the engine in a more streamlined fairing. In total 396 Kawasaki Ki-100 were built before Japan surrendered (Ref.: 24).

Mitsubishi Ki-200 “Shusui” (“Sharp Sword”) (Hasegawa)

TYPE: Interceptor

ACCOMMODATION: Pilot only

POWER PLANT: One Toku-Ro.2 /KR10) bi-fuel liquid rocket, rated at 1,500 kp thrust

PERFORMANCE: 559 mph at 32,808 ft

COMMENT: The Mitsubishi J8M “Shūsui” (literally “Autumn Water”, used as a poetic term meaning “Sharp Sword” deriving from the swishing sound of a sword) was a Japanese WW II rocket-powered interceptor aircraft closely based on the German Messerschmitt Me 163 “Komet” (Comet”). Built as a joint project for both the Japanese Navy and the Army Air Services, it was designated J8M (Navy) and Ki-200 (Army).
The Ki-200 and the J8M1 differed only in minor items, but the most obvious difference was the JAAF’s Ki-200 was armed with two 30 mm Type 5 cannon (with a rate of fire of 450 rounds per minute and a muzzle velocity of 720 m/s, while the J8M1 was armed with two 30 mm Ho-105 cannon (rate of fire 400 rounds per minute, muzzle velocity 750 m/s). The Ho-105 was the lighter of the two and both offered a higher velocity than the German MK 108 cannon of the Messerschmitt Me 163 (whose muzzle velocity was 520 m/s).
The Toko Ro.2 (KR10) rocket motor did not offer the same thrust rating as the original, and Mitsubishi calculated that the lighter weight of the J8M1 would not offset this. Performance would not be as good as that of the Me 163 “Komet”, but was still substantial. The engine still used the German propellants of T-Stoff oxidizer and C-Stoff fuel (hydrogen peroxide/methanol-hydrazine), known in Japan as “Ko” and “Otsu” respectively.
At the end of the war “Shusui” production was already under way. Additionally, the Navy had instructed Mitsubishi, Nissan and Fuji to design a further Navy version as J8M2 with only one cannon thus giving additional space for more fuel and by that more endurance, while the Army ordered Rikugun Kokugijutsu Kenkyujo the development of an enlarged version of the Ki-200 with increased fuel tankage, known as Mitsubishi Ki-202 “Shusui Kai to be built by Mitsubishi (Ref.: 1, 24).

Tachikawa Ki-94-I (A+V Models, Resin)

TYPE: High-altitude fighter. Project

ACCOMMODATION: Pilot in pressurized cockpit

POWER PLANT: One Mitsubishi Ha-211 Ru radial engine, rated at 2,200 hp

PERFORMANCE: 485 mph at 32,810 ft (estimated)

COMMENT: Preliminary discussions regarding a heavily armed high-altitude fighter were held between the Koku Hombu and Tachikawa Hikoki K. K. in mid-1942. The new aircraft was to be fitted with a pressure cabin and capable of reaching a top speed of 490 mph.  The aircraft proposed by Tachikawa, which received the Kita designation Ki-94, was of a highly unconventional design. The aircraft was a large twin-boom monoplane, powered by two 2,200 hp Mitsubishi Ha-211 Ru air-cooled radials which were mounted fore and aft of the pilot’s cockpit and drove four-blade tractor and pusher propellers. The very heavy armament that should have been mounted on the aircraft should have been powerful enough to make short work of most US heavy bombers of that area at that time. A full-scale wooden mock-up of the Ki-94 was ordered and built although at the same time a contract was placed with Nakajima for another high-altitude fighter, the Ki- 87, with less stringent range requirements as a fall-back design for the Tachikawa Ki-94.
Notwithstanding the outstanding prospective performance, which however was judged by the technical department of the Japanese Army Air Force as “unduly optimistic” and too complex, the design was discarded. But in mid-1943 Tachikawa submitted a new proposal to meet the same requirements as the competitive Nakajima Ki-87. In order to avoid confusion the Kitai designation the first Tachikawa design received the designation Ki-94-I, and the new design Ki-94-II (Ref.: 1, 24).

Kogiken Plan I Type A Heavy fighter (Unicraft, Resin)

TYPE: Interceptor, fighter. Project

ACCOMMODATION: Pilot only

POWER PLANT: One Kawasaki Ha 40 liquid-cooled engine, rated at 1,100 hp

PERFORMANCE: No data available

COMMENT: In the summer of 1941, Rikugun Kokugijutsu Kenkyujo (Japanese Army Aerotechnical Research Institute, short named “Kogiken”) formed a design group under the leadership of Ando Sheigo. The task was to study Japanese aviation technology in terms of what was possible at present and in the near future. Additionally, some effort was to be spent on reviewing the aircraft technology of other countries. From the results the group was to assemble and draft proposals for aircraft to fill various pre-determined roles: heavy fighter, light bomber, heavy bomber and reconnaissance. For a bigger idea pool, Imperial Japanese Army (IJA) main aircraft providers, Kawasaki and Tachikawa, were invited to join the group, too. In that period projects such as Kogiken Plan III Revised light bomber and Kogiken Plan V Revised light bomber were designed and proposed to the IJA.
Among fighter designs the Kogiken Plan I Type A was a single seat heavy fighter and a Japanese adaption of the Bell P-39 “Airacobra” mid-fuselage engine concept. The aircraft was designed end 1941 and should be powered by a single Kawasaki Ha 40 liquid-cooled in-line engine, derived from the German Daimler-Benz DB 601A. The engine was installed immediately aft the cockpit driving a four-bladed puller propeller via an extension shaft. A tricycle landing gear was provided similar to the Bell P-39. Armament consisted of 37 mm Ho-203 or 20 mm Ho-5 canon firing through the propeller hub and two wing-mounted 12.5 mm Ho-103 guns. No further details are known, the project never left the drawing board (Ref.: Parts from Unicraft).

Tachikawa Ki-77 (A+V Models, Resin)

TYPE: Long-range Transport and communication aircraft

ACCOMMODATION: Crew of five in sealed oxygen cabin

POWER PLANT: Two Nakajima Ha-115 radial engines, rated at 1,170 hp each

PERFORMANCE: 273 mph at 19,100 ft

COMMENT: The Tachikawa Ki-77 was a Japanese very long-range experimental transport and communications aircraft of World War II derived from a civil design commissioned by the Japanese newspaper “Asahi Shinbun” (“Asahi Press”) to break the flight distance record set by an Italian Savoia-Marchetti S.M.75G.
Ki-77 was the Japanese Army Air Force designation for the civil A-26. The “A” stood for the name of the sponsor Asahi press and “26” for the first two digits of the current Japanese year, 2600 (A. D. 1940).
The overall design was developed by the Aeronautical Research Institute of the University Tokyo together with Tachikawa. It was a clean, slim low wing twin-engine monoplane, and was finalized in autumn of 1940 with the first flight expected in late 1941. But this was canceled with the start of the war against the United States and the reallocation of priorities. The design included a number of novel features, including a high aspect ratio laminar flow wing for reduced drag and a sealed but unpressurized cabin to reduce the need for oxygen masks at its intended operating altitude as well as special low drag cowlings.
In mid 1942, the Japanese decided to forge a link with Europe, but wished to avoid Russian-controlled airspace and development on the Ki-77 was restarted. The first of two prototypes flew on 18 November 1942. The Ki-77 suffered from persistent oil cooling problems which required many changes before being solved, delaying any flight into July 1943. While working on the problem, Tachikawa built a second aircraft that was ready in mid 1943. After several flight trials it was readied for a “Seiko” (Success) mission between Japan and Germany. The aircraft departed Japan on 30 June 1943 for Singapore, where the airstrip had to be lengthened by 1,000 meters to assure a safe take off. Finally, the Ki-77 took off at 7:10 on 7 July 1943 with eight tons of fuel, ample to reach Europe. Their intended destination was a German airfield. The aircraft never reached its destination but disappeared over the Indian Ocean, probably intercepted by British fighters thanks decoding intercepted German communications.
Even if in 1944 the usefulness of record breaking flights was overshadowed by the necessities of war, the Japanese needed a propaganda coup and the surviving Ki-77 was available. On 2 July it flew 19 circuits over a triangular route off Manchuria, landing 57 hours 9 minutes later and covering 10,212 mi at an average speed of 179.1 mph, thus setting a new endurance record. The Ki-77 landed with 800 liters remaining in the tanks of the 3,200 US gal it started with, so the maximum endurance was around 11,000 mi. The Ki-77’s endurance record was never internationally recognized or officiated and was still in existence when Japan surrendered. The aircraft was shipped to the United States aboard the US Navy escort aircraft carrier USS CVE-9 “Bogue” from Yokosuka in December 1945, arriving in the States on January 1946 for examination, before being scrapped (Ref.: 24).